Experimental Study On Fatigue Properties Of Foam Aluminum Sandwich Structure

Aluminum foam has many advantages,such as energy absorption,electromagnetic shielding,sound insulation and noise reduction.It is widely used in aerospace,construction,automotive and other fields.Pure aluminum foam is not of high strength and is not suitable to be used as structural component.But the structure of foam aluminum sandwich composed of compact metal has dual properties of dense metal and foam aluminum,the structure and function are integrated,and the applicatipon scope is greater.At present,the research on the structure of aluminum foam core is mainly quasi static mechanical properties and impact properties,but in practical application,the structure will undergo fatigue load,but the fatigue life of foam aluminum sandwich structure is seldom studied,so it is very urgent to explore the fatigue life of foam aluminum sandwich structure.In this dissertation,fatigue life of sandwich structure with foam aluminum is studied based on experimental research and high-frequency fatigue testing machine.(1)the quasi-static mechanical properties of different aluminum foam sandwich structures are studied through experiments,and the bearing capacity of different structures is obtained.At the same time,the influence of the thickness of the panel and the density of the core on the peak load of the steel plate and aluminum panel sandwich aluminum sandwich structure is studied,which lays a foundation for the fatigue life test.The test results show that the peak load of steel panel and aluminum panel aluminum foam sandwich structure is quite different with the thickness of the panel and core density.(2)the fatigue life of aluminum panel and steel panel aluminum foam core structure under three point bending loading was tested and studied.The effect of panel thickness and core density on the failure mode and fatigue life of aluminum foam sandwich structure was analyzed.The results show that the fatigue life of aluminum panel sandwich structure increases with the increase of core density,but it has no obvious relationship with the thickness of the panel.Compared with the aluminum foam sandwich structure,the increase of the thickness of the panel and the density of the core will lead to the improvement of the fatigue life of the aluminum foam sandwich structure.(3)the failure modes of aluminum panel and steel panel aluminum foam core structure with different thickness and core density are analyzed under three point bending loading conditions.The results show that there are two failure modes in aluminum face foam aluminum sandwich,which are identation and core shear,only thin aluminum panel will appear identation.However,the steel panel aluminum foam sandwich structure only occurs the core shear failure.(4)the three point bending fatigue test of the steel panel foam aluminum sandwich structure under different stress levels was carried out.The S-N curve was established by single point method,and the influence of different stress levels on the structure was analyzed.Based on the maximum likelihood method,the p-S-N curve of the sandwich structure of aluminum foam is established,and the influence of the thickness of the panel and the density of core on the fatigue life under different reliability is analyzed.